An advice service has been proposed (Japanese Patent Application Laid-open No. 2001-195568) wherein a subject transmits an image of his or her own face, including hair, to an information provider such as a maker of hair care products, and the information provider, using a calculating means, forms a simulation image wherein the hair region in that image is changed to the hair color desired by the subject and provides to the subject the simulated image and information related to the hair dye required to achieve, with the subject's hair, the hair color in that simulated image. In this case, distinguishing the hair region and the non-hair region of the original image is automatically done by means of a calculating device, based on such things as brightness, hue, and the continuity of changes thereto.
In recent years, communications networks such as the Internet have advanced and, moreover, even camera-equipped mobile telephones which utilize the Internet have come into widespread use, and thus it is expected that this advice system can be utilized easily and extensively by subjects.
However, for many images transmitted by subjects there are cases where, if the hair region is identified from those images based on a standardized reference, such as hue, the hair region cannot be accurately identified due to differences in photo-taking conditions such as camera model and lighting. Particularly in cases where the hair color is a light blonde, and hue and brightness are close to skin color, this tendency is large.
As a method for identification of the hair region, a method is known (Japanese Patent Application Laid-open No. H11-188183) wherein a region corresponding to the hair region is chosen from a two-dimensional image by dividing the two-dimensional image into the same hue regions, identifying the same hue and continuous regions and conducting matching with a prepared template. However, with this method, the hair region may not be identified accurately, for example, in the case where the hue of the skin color and the hair color are similar to each other and where the background is not a solid color.